1. Field of the Invention
The present invention relates to the overall design and construction of a novel three-wheeled vehicle designed for road use. Particularly, the present invention relates to a novel three-wheeled straddle-type vehicle having a split radiator associated with the engine. The split radiator includes a pair of radiators that are fluidly connected and located on opposite sides of the vehicle frame, whereby a storage compartment may be located in the front of the vehicle normally reserved for the radiator.
2. Description of Related Art
There are numerous known vehicles powered by internal combustion engines, which are designed for road use and/or off road use. All of these vehicles have special cooling parameters.
One such vehicle is an all terrain vehicle (ATV) having two front wheels, two rear wheels and a saddle type seat. The cooling system and in particular the radiator associated with the engine for an ATV is typically located in the front center of the vehicle. The radiator is also positioned fairly high on the vehicle so that the radiator is not slashed with mud. This arrangement does not permit the location of a storage compartment in the front of the vehicle. ATV's typically have a higher center of gravity compared to other vehicles. To lower the center of gravity, the radiator in the ATV may be forwardly disposed at an angle. The angle, however, must be greater than 45° so that the radiator will not contact the ground when the ATV travels down a hill.
Attempts have been made to modify an ATV to produce a straddle-type three-wheeled vehicle with two front wheels and one rear wheel. For example, U.S. Pat. No. 4,787,470 discloses a three-wheeled vehicle with two front wheels and a sole rear wheel having a body formed by an ATV frame carrying two front and one rear fenders and a saddle type seat. An engine is supported on the frame but is exposed to the exterior of the vehicle body, much like as done in motorcycles. In such a vehicle, the center of gravity of the rider and the vehicle are located higher off the ground than the vehicle contemplated by the present invention.
Another known vehicle is the motorcycle having one front wheel and one or more rear wheels. Like the ATV, the radiator for the cooling system is located in the front center of the motorcycle. With this arrangement, the motorcycle has a higher center of gravity. The location of the radiator is fixed so that it does not contact the rider and interrupt the handling of the motorcycle. This location of the radiator does not permit a forwardly located storage compartment.
Another vehicle is a snowmobile, which is designed for trail use and off-train use. The radiator associated with the cooling system for the snowmobile is located in the rear center of the snowmobile in the tunnel beneath the snowmobile. With this location, snow from the drive belt contacts the radiator to cool the engine.
Attempts have also been made to modify a snowmobile to produce a straddle-type three-wheeled vehicle. U.S. Pat. No. 4,662,468 also discloses a three-wheeled vehicle with two front wheels and a sole rear wheel. The three-wheeled vehicle of the '468 patent uses a conventional snowmobile chassis, which has been modified to attach two driving wheels at its front portion.
U.S. Pat. No. 5,564,517 discloses a snowmobile conversion frame kit which includes a frame having two wheels with a steering assembly in the front and a single wheel with a swing arm in the rear. The kit in the '517 patent is designed to be secured to a conventional snowmobile chassis also. Conventional snowmobile chassis offer less rigidity and structural strength than are required for the all-terrain vehicles. None of these vehicles provide adequate cooling for a three-wheeled vehicle having a low center of gravity as contemplated by the present invention.